Apparatus and method for transporting contact lenses through dipping baths

ABSTRACT

There is described an apparatus and method for transporting contact lenses through dipping baths ( 2, 3, 4 ) for e.g. rinsing, extraction, coating or loading purposes. The lenses are individually accommodated in respective containers ( 5 ) which are capable of enabling a flow of treatment fluid (S) into and out of the container ( 5 ). During their automatic transport through the dipping baths ( 2, 3, 4 ) the containers ( 5 ) are held in carriers ( 6 ). Lifters ( 9 ) are provided for automatically lowering and raising the carriers ( 6 ) in a reciprocating manner along their travel through the dipping bath ( 2, 3, 4 ). The reciprocating lowering and raising of the containers ( 5 ) is accomplished such, that a portion of each container which accommodates a contact lens remains immersed in the treatment fluid (S) which is contained in the dipping bath ( 2, 3, 4 ) while the container ( 5 ) suspended from the carrier ( 6 ) is advanced through the dipping bath ( 2, 3, 4 ) from a starting end to a leaving end thereof.

This application is a division of U.S. patent application Ser. No.12/904,179, filed Oct. 14, 2010 which claims the benefit under 35 U.S.C.§119(e) of United States provisional Application No. 61/252,498, filedon Oct. 16, 2009, each of which is incorporated by reference in itsentirety.

FIELD

The invention relates to an apparatus for transporting contact lenses indipping baths for treatments such as rinsing, extraction, coating orloading purposes. The invention also relates to a respective method forthe transport of the contact lenses in or through dipping baths orprocesses.

BACKGROUND

It is well established in the art to produce hard and soft contactlenses in an automated production process with reusable moulds.Depending on the material from which the contact lenses are made, and inaccordance with the production method applied the contact lenses must beimmersed in extraction solutions, and/or rinsing solutions and/orcoating solutions and/or loading solutions in order to obtain thedesired lens product which may be worn in direct contact with a wearer'seyes. During these process steps it must be ascertained that the entirecontact lens is sufficiently wetted and treated with the respectivetreatment fluid. The contact lenses are usually accommodated or heldindividually in respective containers and transported inside thesecontainers through a number of dipping baths which are filled with therespective treatment fluid. In order to have the lenses properly wettedand treated it must be ascertained that the treatment fluid comes intocontact with all sides of the contact lenses. Care must be taken that noportion of the contact lens is “shaded-off” by the walls of thecontainer. The transport of the contact lenses through the dipping bathsmust be accomplished automatically, and the lenses must not be exposedto undue strain due to excessive agitation in order to avoid the risk ofdamage. The transport of the contact lenses through the dipping bathsshould be carried out smoothly, with the entire lens freely floating inthe treatment fluid.

It is therefore an object of the present invention to provide anapparatus and a method for transporting contact lenses through dippingbaths, while ensuring that the contact lenses are properly wetted andimmersed in the respective treatment fluid. The apparatus and the methodshall be compatible with the continuous production processes for contactlenses.

SUMMARY

These and still further objects are met by an apparatus for transportingcontact lenses through dipping baths for treatment such as rinsing,extraction, coating or loading purposes which includes the featureslisted in claim 1. The objects are also met by a respective processingmethod which comprises the process steps listed in the respectiveindependent method claim. Further improvements of the invention andpreferred embodiments are subject of the respective dependent claims.

In accordance with one embodiment of the present invention, an apparatusfor transporting contact lenses through dipping baths for treatment isdisclosed. The apparatus includes a plurality of containers each foraccommodating (i.e., holding within) one contact lens, the containerscapable of enabling a flow of one or more treatment fluid into and outof the container, and a plurality of carriers to hold the containersduring transport through the dipping baths, and further includinglifters to automatically lower and raise the carriers in a reciprocatingmanner along a transport path through the dipping baths, such that aportion of each container which holds a contact lens remains immersed inthe treatment fluid contained in the dipping bath while the containerheld by the carrier is transported through the dipping baths from astarting end to a leaving end thereof.

The contact lenses are transported through the dipping baths in atranslational movement which is superimposed by a lowering and raisingmotion. During these superimposed manipulations that portion of thecontainers in which the contact lenses are accommodated or held isalways completely immersed in the treatment fluid. Thus, the contactlenses are constantly agitated by treatment fluid streaming into and outof the container. Due to this agitation the contact lenses do not restagainst a surface of the container but rather are held in suspension inthe treatment liquid. Thus, it is ensured that all sides of the contactlenses are properly wetted by the treatment fluid. The treatment fluidis continuously streaming into and out of the container accommodating alens. Thus, it is constantly being exchanged and the contact lens isexposed to fresh treatment fluid. The streaming velocity of thetreatment fluid, however, is low enough to avoid an excessive agitationof the contact lens, so that it is not affected in a negative manner.

For constructive reasons it proves advantageous if the lifters thatreciprocatingly lower and raise the carriers are mounted at thelongitudinal sides of a housing of each dipping bath. The housings ofthe dipping baths usually are of a rectangular shape, having a certaindepth. The longitudinal sides of the housings provide enough space formounting the lifters and are easily accessible.

In an effective embodiment of the apparatus the lifters comprise a guidebar at each longitudinal side of the housing of a dipping bath. Theguide bars slidingly support the longitudinal ends of the carriers, inwhich the containers accommodating the contact lenses are held.

At their supporting faces the guide bars each are provided with alongitudinally extending groove. Cams provided at the longitudinal endsof the carriers are accommodated in these grooves. Thus, the carriersare secured against an axial dislocation.

In order to provide the desired vertical movement of the guide bars theyare each connected with a lever which is reciprocatingly lowered andraised. The levers extend about vertically at the longitudinal sides ofthe housings of the dipping baths.

For having the levers reciprocatingly lowered and raised they areconnected with an electric drive. The stroke of the vertical movement ofthe levers is adjustable. Thus, depending on the size of the containersin which the contact lenses are transported, the lever may be loweredand raised different distances.

It proves convenient and sufficient for the usually applied sizes of thecontainers if the stroke of the levers is adjustable in between 2 mm to20 mm, preferably 6 mm to 15 mm, most preferred 10 mm to 12 mm.

In one embodiment of the apparatus the electric drive is controlled fora continuous revolution and the stroke is mechanically adjustable. In analternative embodiment of the apparatus the stroke of the levers isadjustable by control of a degree of a reciprocating forward andbackward revolution of the electric drive. This last embodiment enablesa very fast and effective control of the stroke. The first embodimentwith mechanical adjustment allows the application of simpler controlmeans for the electric drive. On the other hand though, the mechanicaladjustment is less convenient.

The transport of the carriers through each dipping bath is accomplishedby endless conveyor belts or chains which are provided at thelongitudinal sides of the housing of the dipping bath. Along theircircumference the conveyor belts or chains are equipped with pusher dogsthat protrude from the surface. The longitudinal ends of the carrierseach are placed in between two protruding pusher dogs. The length of thepusher dogs is greater than the stroke of the vertical movement of thecarriers.

The transport of the contact lenses through each dipping bath may beaccomplished in a continuous manner or stepwise. In a stepwise transportthe transversal movement of the carriers and the vertical lowering andraising thereof are accomplished sequentially.

In dipping bath processes, e.g. for rinsing, extraction, coating orloading of the contact lenses, for the avoidance of dilution andcontamination it may be advantageous if sequential arrangements of anumber of dipping baths with the same treatment fluid are provided. Insuch cases the carriers holding the containers with the contact lensesmust be transported from one dipping bath to the next one. For thatpurpose the apparatus according to the invention further comprises anautomatically operating transfer means for the carriers from one dippingbath to the next dipping bath along the transport path.

The transfer means is a pair of transversally spaced transfer wheelswith starlike arranged radial slots for receiving the longitudinal endsof the carriers. The pairs of transfer wheels are provided integrallywith the means for the superimposed translational and vertical movementof the carriers. The control of the respective drives is such, that atthe starting end of a housing of a dipping bath the carriers aretransferred to the conveyor belt or chain such, that the longitudinalends of the carriers each are placed in between two successive pusherdogs. In the next step the carriers are transported on by the conveyorbelts or chains before being lowered. At the leaving end of the housingthe carriers are transferred into the radial slots of the transferwheels.

For increasing the productivity each carrier along its length is adaptedfor receiving side by side a number of containers, each accommodating anindividual contact lens. This allows the simultaneous treatment of alarger number of contact lenses disposed in containers that are arrangedside by side. In an exemplary embodiment of the invention a singlecarrier may hold up to 14 containers, each accommodating a singlecontact lens.

In accordance with another embodiment of the present invention, a methodfor transporting contact lenses through dipping baths for treatment isdisclosed. The method for transporting contact lenses through dippingbaths includes the steps of individually accommodating contact lenses inrespective containers which are capable of enabling a flow of one ormore treatment fluids into and out of the container, holding thecontainers in carriers, advancing the containers through the dippingbaths, subjecting the carriers for the containers to a reciprocatinglowering and raising motion along the transport through the dippingbaths, wherein a portion of each container which accommodates a contactlens remains immersed in the treatment fluid contained in the dippingbath while the container held by the carrier is transported through thedipping baths from a starting end to a leaving end thereof.

The contact lenses are transported through the dipping baths in atranslational movement which is superimposed by a vertical lowering andraising motion. During these superimposed motions that portion of thecontainers in which the contact lenses are accommodated is alwayscompletely immersed in the treatment fluid. Thus, the contact lenses areconstantly agitated by treatment fluid streaming into and out of thecontainer. Due to this agitation the contact lenses do not rest againsta surface of the container but rather are held in suspension in thetreatment liquid. Thus, it is ensured that all sides of the contactlenses are properly wetted by the treatment fluid. By the agitation ofthe containers held in the carriers the treatment fluid is forced tocontinuously stream into and out of the container. Thus, it isconstantly being exchanged and the contact lens in the container isexposed to fresh treatment fluid. The streaming velocity of thetreatment fluid, however, is low enough to avoid an overly agitation ofthe contact lens, so that it is not effected in a negative manner.

At the starting end of a dipping bath the containers held in thecarriers are first lowered from an upper position into the dipping bath.By this measure the contact lenses are raised from the bottom of thecontainer and remain floating and suspended in the treatment fluidduring the transport through the dipping bath.

The superimposed translational and vertical movement of the carriers iscontrolled such, that a transport path of the containers for the contactlenses follows approximately a sinus curve.

The transport of the carriers and the vertical movement thereof may beaccomplished continuously. However, for a better control of thesuperimposed translational and vertical movements it proves advantageousif the translational transport of the containers held in the carriersthrough the dipping baths and the lowering and raising, respectively,thereof are accomplished sequentially.

In order to avoid overly diluting and a contamination of the treatmentfluids from preceding to successive baths the contact lenses may betransported through a number of successively arranged dipping baths withtreatment fluid. At the transition from one dipping bath to the next onethe carriers holding the containers for the contact lenses aretransferred such, that the containers due to gravity are suspended fromthe carriers with their bottoms extending approximately verticallytowards the dipping baths. Thus, in the transfer means the longitudinalends of the carriers are supported loosely such, that they may turn inaccordance with the action of gravity.

These and still further features of the apparatus and the respectivetransport method will become apparent from the following description ofan exemplary embodiment of the invention, reference being made to thedrawings, which are not to scale, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view from above of a dipping bath with atransport

-   -   i. apparatus;

FIG. 2 is a side view of a dipping bath of FIG. 1 with the transportapparatus in

-   -   ii. the lowered position; and

FIG. 3 is a side view of the dipping bath of FIG. 2 with the transportapparatus in

-   -   iii. the raised position.

DETAILED DESCRIPTION

The following description of an exemplary embodiment of the invention isfor illustrative purposes only and not intended for limitation of thescope of the invention.

FIG. 1 is an exemplary depiction of an apparatus or arrangement e.g. ofsuccessive dipping baths for rinsing, extraction, coating and/or loadingof contact lenses during the fabrication process. The arrangement ofdipping baths is generally designated with reference numeral 1. Itcomprises a number of successive dipping baths, three of which aredesignated with reference numerals 2, 3, and 4. The dipping baths 2, 3,4 are, e.g., for lens rinsing, extraction, coating or loading purposesand contain the same kind of treatment fluid S in differentconcentrations inside basin-like housings 20, 30, and 40. A treatmentfluid may suitably be one or more liquids or solutions used to treat thecontact lens. The contact lenses are individually accommodated intube-like containers 5 which are held in side by side relationship incarriers 6. The carriers 6 are transported along a transport path Tthrough the dipping baths 2, 3, 4, with that portion of the containers5, in which the contact lenses are accommodated, completely immersed inthe treatment fluid S. For transporting the carriers 6 together with thecontainers 5 through the dipping baths 2, 3, 4 each dipping bath isprovided at the sides of its respective housing with transport means.The transport means for the carriers are two parallel endless conveyorbelts 7 which are provided with upright standing pusher dogs 70. Thecarriers 6 are placed onto the endless conveyor belts 7 such, that theirlongitudinal ends 60 are located in between two succeeding pusher dogs70. The endless conveyor belt 7 is guided over pulleys. One of thepulleys is driven by an electric drive via a transmission belt.

At the start of each dipping bath and in between successive dippingbaths there are provided transfer means for the carriers 6. The transfermeans are a pair of transfer wheels 8 which are spaced from each otherin a transversal direction and are located next to the side walls of thehousings 20, 30, 40. The transfer wheels 8 are provided with radialslots 80 for receiving the longitudinal ends 60 of the carrier 6. Thetransfer wheels 8 are connected by an axle and electrically driven.

At the sides of the housings 20, 30, 40 of the dipping baths 2, 3, 4there are provided lifters 9 for automatically lowering and raising thecarriers 6 in a reciprocating manner along their transport through thedipping baths. The lifters 9 are electrically driven.

The control of the electric drives for the automatic transport means 7,the lifters 9 and the transfer means 8 are adjusted with respect to eachother such, that during the transport across the dipping baths thatportion of the containers 5, in which the contact lenses areaccommodated, remain completely immersed in the treatment liquid, evenas the carriers are raised by the lifters 9. The controls are furtheradjusted such, that the carriers 5 are securely transferred from thetransfer means 8 to the transport means 7 at the starting end of adipping bath, and at the leaving end of the dipping bath received by theslots 80 in the transfer wheels 8 of the transfer means 8 to the nextdipping bath.

FIGS. 2 and 3 show in greater detail one dipping bath of the arrangementof successive dipping baths 1 of FIG. 1, e.g. dipping bath 2. FIG. 2shows the lifters 9 in the lowered position while FIG. 3 shows thelifters 9 in its raised position. The dipping bath 2 comprises abasin-like housing 20 in which the respective treatment fluid iscontained. An endless conveyor belt 7 with protruding pusher dogs 70 isprovided for the transport of the carriers 6, in which the containersfor the contact lenses are held, through the dipping bath 2 in transportdirection T. It is to be noted that instead of a conveyor belt also aconveyor chain may be used. The longitudinal ends of the carriers 6 aredesignated with reference numeral 60. The endless conveyor belt 7 isguided over pulleys 71, 72, 73. A fourth pulley is covered by a cover ofthe transfer means 8 at the starting end of the housing 20 of thedipping bath 2. One of the pulleys, for example according to FIG. 2pulley 72, may be electrically driven. For that purpose an electricdrive with a drive wheel 75 and a transmission belt 76 is provided.

The transfer means at the starting end of the housing 20 of the dippingbath comprise a pair of transfer wheels 8 with slots 80 for receivingthe longitudinal ends 60 of the carriers. The slots 80 are dimensionedsuch, that the carriers 6 are capable of sliding into and out of them.In the slots 80 the longitudinal ends 60 of the carriers 6 are heldfreely such that they can turn in accordance to the force of gravity onthe containers held in the carriers 6. Thus, it is ensured that thebottoms of the containers always are directed downwardly towards thedipping bath. One of the transfer wheels 8 of the transfer means iselectrically driven. For that purpose there is provided an electricdrive 85 with a transmission belt 86. According to FIG. 2 thetransmission belt 86 drives an intermediate wheel 82, which is connectedwith another wheel 81 at the drive side of the transfer wheel 8 viaanother transmission belt 83.

The lifters for the carriers 6 is generally designated with referencenumeral 9. It comprises a guide bar 90 at each longitudinal side of thehousing 20 of the dipping bath 2. The guide bar 90 slidingly supportsthe longitudinal ends 60 of the carriers 6. At their supporting surfacesthe guide bars 90 preferably are provided with longitudinally extendinggrooves (FIG. 1, reference numeral 99) for receiving corresponding cams(not shown) at the ends 60 of the carriers. The cams may be shaped e.g.as radially protruding flanges.

For reciprocatingly lowering and raising the guide bars 90 in accordancewith the vertical directions double arrow V in FIG. 2, the guide barsare each connected with a lever 91 which is mounted on an excenter disk92 provided at the longitudinal side of the housing 20. The excenterdisk 92 is driven by an electric drive with drive wheel 95 via atransmission belt 96. By control of a reciprocating forward and backwardrevolution of the electric drive the degree of lowering and raising ofthe guide bars 90 may be controlled. Thus, rather than mechanically, thestroke of the lifters 9 is adjusted electronically. It is to be notedthough, that the electric drive may be a continuous one and theadjustment of the stroke may be accomplished mechanically. In theexemplary embodiment of the invention the stroke of the lifters may beadjustable from about 2 mm to about 20 mm. In other embodiments, thestroke of the lifters may desirably be adjustable from about 6 mm toabout 15 mm, while in others the stroke may desirably be adjustable fromabout 10 mm to about 12 mm.

In FIG. 3 the lifter 9 is shown in its raised position. Like referencenumerals designate like elements as in FIG. 2. With the lifters 9 intheir raised position the guide bars 90 extend beyond the conveyor belt7. The length of the pushing dogs 70 on the conveyor belt 7, however, islonger than the maximum stroke of the lifters 9. Thus, it is ensuredthat the longitudinal ends 60 of the carriers 6 remain in engagementwith the pushing dogs 70 protruding from the conveyor belt 7.

In operation the containers suspended from the carriers 6 are firstlowered into the dipping bath 2 in order to ensure that the current ofthe agitated treatment fluid entering the containers keeps the contactlens within each container floating. Upon further transport through thedipping bath in transport direction T the carriers are reciprocatinglyraised and lowered which is indicated by the double arrow V. Thetransport of the contact lenses in the containers through the dippingbath 2 and the reciprocating lowering and raising motion may beaccomplished simultaneously. In an alternative embodiment of theinvention the lowering and raising motion and the transport movement maybe accomplished stepwise, with the containers first being lowered, thentransported on, then raised again, then transported on, then lowered,etc. Ideally, with the superimposed translational and verticalmovements, the transport path of the containers through the dipping bath2 follows a path similar to the path approximated by a sinus curve.

The invention claimed is:
 1. An apparatus for transporting contactlenses through dipping baths, the apparatus comprising a plurality ofcontainers each for accommodating one contact lens, the containerscapable of enabling a flow of one or more treatment fluid into and outof each container, and a plurality of carriers to hold the containersduring transport through the dipping baths, and further comprisinglifters to automatically lower and raise the carriers in a reciprocatingmanner along a transport path through the dipping baths, such that aportion of each container which holds a contact lens remains immersed ina treatment fluid contained in each dipping bath while the containerheld by a carrier is transported through the respective dipping bathsfrom a starting end to a leaving end thereof; wherein the lifters aremounted at longitudinal sides of a housing of each dipping bath, thelifters comprise a guide bar at each longitudinal side of the housing ofthe dipping bath for slidingly supporting longitudinal ends of thecarriers, and the guide bars at their supporting faces each are providedwith a longitudinally extending groove for accommodating a correspondingcam at each longitudinal end of the carriers.
 2. The apparatus accordingto claim 1, wherein the guide bars each are connected with a lever whichis capable of being reciprocatingly lowered and raised.
 3. The apparatusaccording to claim 2, wherein the levers are connected with an electricdrive and are reciprocatingly lowered and raised with a stroke which isadjustable.
 4. The apparatus according to claim 3, wherein the stroke isadjustable from 2 mm to 20 mm.
 5. The apparatus according to claim 4,wherein the stroke is adjustable from 6 mm to 15 mm.
 6. The apparatusaccording to claim 3, wherein the electric drive is controlled for acontinuous revolution and the stroke is mechanically adjustable.
 7. Theapparatus according to claim 3, wherein the stroke of the levers isadjustable by control of a degree of a reciprocating forward andbackward revolution of the electric drive.
 8. The apparatus according toclaim 1, further comprising an automatically operating transfer meansfor transferring the carriers from one dipping bath to the next dippingbath along the transport path.
 9. The apparatus according to claim 8,wherein the transfer means is a pair of transversally spaced transferwheels with radial slots for receiving longitudinal ends of thecarriers.
 10. An apparatus for transporting contact lenses throughdipping baths, the apparatus comprising a plurality of containers eachfor accommodating one contact lens, the containers capable of enabling aflow of “one or more treatment fluid into and out of each container”,and a plurality of carriers to hold the containers during transportthrough the dipping baths, and further comprising lifters toautomatically lower and raise the carriers in a reciprocating manneralong a transport path through the dipping baths, such that a portion ofeach container which holds a contact lens remains immersed in atreatment fluid contained in each dipping bath while the container heldby a carrier is transported through the respective dipping baths from astarting end to a leaving end thereof, wherein the lifters are mountedat longitudinal sides of a housing of each dipping bath, and whereineach carrier along its length is adapted for receiving side by side anumber of containers, each accommodating an individual contact lens. 11.The apparatus according to claim 10, wherein the lifters comprise aguide bar at each longitudinal side of the housing of a dipping bath forslidingly supporting longitudinal ends of the carriers.
 12. Theapparatus according to claim 11, wherein the guide bars at theirsupporting faces each are provided with a longitudinally extendinggroove for accommodating a corresponding cam at each longitudinal end ofthe carriers.
 13. The apparatus according to claim 12, wherein the guidebars each are connected with a lever which is capable of beingreciprocatingly lowered and raised.
 14. The apparatus according to claim13, wherein the levers are connected with an electric drive and arereciprocatingly lowered and raised with a stroke which is adjustable.15. The apparatus according to claim 14, wherein the stroke isadjustable from 2 mm to 20 mm.
 16. The apparatus according to claim 15,wherein the stroke is adjustable from 6 mm to 15 mm.
 17. The apparatusaccording to claim 14, wherein the electric drive is controlled for acontinuous revolution and the stroke is mechanically adjustable.
 18. Theapparatus according to claim 14, wherein the stroke of the levers isadjustable by control of a degree of a reciprocating forward andbackward revolution of the electric drive.
 19. The apparatus accordingto claim 18, further comprising an automatically operating transfermeans for transferring the carriers from one dipping bath to the nextdipping bath along the transport path.
 20. The apparatus according toclaim 19, wherein the transfer means is a pair of transversally spacedtransfer wheels with radial slots for receiving longitudinal ends of thecarriers.